What You Need to Prepare for Online Tax Filing 2026: Summary of Procedures, Deductions, and How to Check Your Tax Refund

A 2026 online tax filing guide for salaried employees and freelancers, summarizing the 2025 tax deduction items, filing steps via the Revenue Department's website, and how to track your tax refund for the fastest receipt.

At the start of 2026, a key task for working people is filing their personal income tax for the 2025 tax year. This year, new tax deduction measures have been introduced to provide substantial support, including economic stimulus and sustainable investment incentives. For those wondering what documents to prepare, the filing process, and how long refunds will take, we have compiled all the information in one place.

When does online tax filing for 2026 begin?

For personal income tax returns for the 2025 tax year (filed during 2026), the deadlines are as follows.

• Paper filing: from 1 January to 31 March 2026.
• Online filing (e-Filing): extended until 8 April 2026.

By law, if your income meets the threshold, you must file a tax return even if no additional tax is owed after calculation. The basic rule for first-timers is that single individuals earning over 120,000 baht per year must file a tax return immediately, even though everyone automatically receives a personal deduction of 60,000 baht.

What documents should you prepare before filing taxes?

To ensure smooth and speedy filing, these documents should be prepared in digital file format.

• Certificate of income and tax withheld (Form 50 Tab Wi): summarizes annual income and taxes withheld at source.
• Deduction details: prepare the ID numbers of persons you claim deductions for, such as parents or children.
• Investment evidence: certificates from funds (ThaiESG, RMF) or life insurance.
• Full tax invoices: for the E-Receipt 2.0 program.

Overview of tax deduction entitlements for 2025 (for filing in 2026).

According to the latest data, deductions are divided into four main groups that help reduce your tax burden or increase your refund, as follows.

1. Personal and family group.

• Personal deduction: 60,000 baht (automatically granted to everyone).
• Spouse (no income): 60,000 baht.
• Children: 30,000 baht each (for the second child onwards born in 2018 or later, 60,000 baht each).
• Antenatal and childbirth expenses: actual payments up to 60,000 baht.
• Parental care (age 60 or older): 30,000 baht per parent.

2. Insurance, savings, and investment group.

• Social security: up to 9,000 baht.
• Life insurance/savings: actual payments up to 100,000 baht.
• Personal health insurance: up to 25,000 baht (combined with life insurance, total not exceeding 100,000 baht).
• ThaiESG funds: deductible up to 30% of income, not exceeding 300,000 baht (held for 5 years).
• RMF/PVD funds: combined deduction limit of 500,000 baht.

3. Economic stimulus group.

• Solar Rooftop: installation costs for solar panels at residences deductible up to 200,000 baht (per Revenue Department announcement).
• E-Receipt 2.0: for purchases of goods and services (16 Jan - 28May2025) deductible up to 50,000 baht.
• Home loan interest: deductible actual amount, up to 100,000 baht.

4. Donations (supporting society with double deduction rights).

• Education, sports, government hospitals: deductible double the amount paid (not exceeding 10% of income after other deductions).
• General donations: actual amount paid (not exceeding 10% of income after other deductions).
• Political party donations: not exceeding 10,000 baht.

It is recommended to donate via the e-Donation system to send information directly to the Revenue Department without paper receipts.

Steps for online tax filing in 2026.

Tax filing is now easy through the Revenue Department's E-Filing system, with the following steps.

1. Access the website: go tothe Revenue Departmentselect online filing.
2. Login: use your national ID number and password (if forgotten, reset via phone number).
3. Review data: the My Tax Account system will display income and some deductions automatically submitted, such as social security and home loan interest.
4. Add information: enter other income and prepared deductions, such as donations or investments in various funds.
5. Review and confirm: the system will calculate immediately whether you need to "pay more" or "receive a refund."

After filing, how long does it take to receive a refund?

A common question. Normally, if all information is complete and no further document verification is required, refunds are received within 7-15 working days. However, if randomly audited or documents are unclear, it may take 1-3 months. Linking your PromptPay account with your ID number helps you get refunds as quickly as possible.

Filing taxes is not intimidating if you prepare and gather deduction documents early, especially with new benefits in 2025 such as Solar Rooftop and the updated ThaiESG fund. Filing online via E-Filing is not only convenient but also speeds up refunds through the PromptPay system.